Metering device

ABSTRACT

A pump for dispensing a metered amount of liquid, such as milk, having a reciprocating pumping cylinder. Dispensing into the ultimate container is through a nozzle located above a conveyor path and connected to the pumping cylinder outlet by a conduit. The nozzle opens and closes in response to fluid pressure. It is designated to minimize foaming while providing fast dispensing and maintenance-free operation. To allow the pumping cylinder to be driven at high speed on its intake stroke, a damping device is provided which cushions the end of this stroke and is arranged to operate independently of changes which may be made in the length of the stroke.

United States Patent Encke [54] METERING DEVICE [72] lnventor: Robert B. Encke, Mount Vernon,

Iowa

[73] Assignee: Cherry-Burrell Corporation,

Chicago, Ill.

[22] Filed: April 9, 1971 [21] Appl. No.: 132,688

[52] US. Cl. ..l4l/59, 92]] 3.8, 92/85, 141/286, 222/309, 239/453, 417/399 [51 1 Int. Cl ..B65b 3/18, B65b 3/22 [58] Field of Search ..14l/4-7, 46, 47-53,

[56] References Cited UNITED STATES PATENTS 3,491,919 1/1970 Ramsay ..222/309 '51 Aug. 22, 1972 Primary Examiner-Houston S. Bell, .Ir. Attorney-Fitch, Even, Tabin & Luedeka ABSTRACT A pump for dispensing a metered amount of liquid,

such as milk, having a reciprocating pumping cylinder.

Dispensing intothe ultimate container is through a nozzle located above a conveyor path and connected to the pumping cylinder outlet by a conduit. The nozzle opens and closes in response to fluid pressure. it is designated to minimize foaming while providing fast dispensing and maintenance-free operation. To allow the pumping cylinder to be driven at high speed on its intake stroke, a damping device is provided which cushions the end of this stroke and is arranged to operate independently of changes which may be made in the length of the stroke.

11 Claims, 6 Drawing figures Patented Aug. 22, 1972 3,685,554

2 Sheets-Sheet I.

FIG.|

INVENTOIZ 6% 205527 5 Eva z 156k, ML Tm, 14%

AT T (5,

METERING DEVICE The present invention relates to fluid handling, and more particularly to a metering pump of the type for flowing a foamable liquid in a predetermined amount into a container.

In employing a metering pump for flowing a foamable liquid, such as milk, into containers, it is often difficult to prevent foaming of the liquid, with the result that the containers may be improperly filled or portions of the liquid may be wasted. If the valve employed in the metering pump for controlling the flow of the liquid is closed too rapidly, it may rebound and cause liquid to spit through the valve opening. If the valve in the pump is closed too slowly, the liquid, e.g. milk, may foam if the momentum of the liquid causes an extra discharge that creates voids in the liquid in the valve which are filled by air. Furthermore, the air initially within the container being filled is displaced by the entering liquid, and accommodation must be provided for this air to leave the container in the vicinity of the delivery nozzle, particularly when flowing a foamable liquid.

In US. Pat. No. 3,285,300, apparatus is illustrated including a cylinder having a piston which reciprocates therein to draw a liquid, such as milk, into the cylinder through an inlet on the upstroke and to discharge the liquid from the cylinder through an outlet on the downstroke. A pair of coaxial closures are located in the outlet, which are opened by the force of the liquid being dispensed. A tapered plug is positioned in the outlet between the closures to fill a portion of the crosssectional area of the nozzle. A radially extending plate is mounted on the upper surface of the lower closure so that air can escape from the container being filled through a gap in the discharge path of the liquid entering the container to minimize foaming of the liquid being dispensed.

Although the nozzle apparatus shown in US. Pat. No. 3,285,300 has enjoyed commercial success in the field of flowing foamable liquids, more effective arrangements are desired which will resist leakage over long periods of use and allow flexibility in nozzle location. Moreover, apparatus is desired which pemiits even more rapid dispensing of a foamable liquid without foaming. Arrangements are desired which are particularly suited to machine for filling with greater capacities which facilitate refilling the pumping cylinder at a rate much faster than the rate at which liquid is dispensed.

Hence, an object of the present invention is to provide an improved metering pump suitable for flowing a V foamable liquid.

Another object of the present invention is to provide an improved metering pump suitable for flowing a foamable liquid.

Another object of the invention is to provide an improved nozzle for directing a foamable liquid, such as milk, into a predetermined amount into a container without excessive foaming.

Still another object of the invention is to provide an improved metering pump for liquid dispensing which is capable of rapidly refilling the pumping cylinder and terminating the inflow of the liquid thereinto without spitting or foaming of liquid at the location where it is being dispensed.

These and other objects of the invention will become apparent from' a reading of the following detailed description with reference to the accompanying drawings, in which:

FIG. 1 is an elevational view, partly in section, of a metering pump of the type for flowing a foamable liquid in a predetermined amount into a container;

FIG. 2 is a perspective view of the discharge valve element of the pump shown in FIG. 1;

FIG. 3 is a sectional elevational view of the discharge portion of the pump shown in FIG. 1;

FIG. 4 is a cross-sectional view taken along the line 4-4 in FIG. 3;

FIG. 5 is a sectional elevational view of the damping and adjusting units employed in the pump shown in FIG. 1; and

FIG. 6 is a perspective view of a portion of the damping unit shown in FIG. 5.

Very generally, and with reference to FIG. 1 of the drawing, there is shown a metering pump designated by the reference numeral 10 of the type for flowing a foamable liquid, e.g. milk, in a predetermined amount into a container without excessive foaming. The pump 10 forms the filling section of a machine for packaging milk or other liquid, such as a machine of the type shown in US. Pat. No. 3,486,423, and generally includes a cylinder 12 in which a piston 14 reciprocates. As the piston retracts within the cylinder, it draws liquid through an inlet 16 into the cylinder, and as the piston advances within the cylinder, it forces the liquid under pressure through an outlet 18 into a nozzle 20 for directing the liquid into a container. Within the nozzle 20 there is located a hollow discharge valve element 22 which is operated by the liquid pressure to allow the liquid to be dispensed through a 369 annular passageway. The air displaced from the container by the liquid passes through the interior of the hollow valve elements 22 and vents to the atmosphere.

More particularly, the cylinder 12, into which the liquid to be dispensed is first drawn through the inlet 16, has a capacity for pumping a predetermined amount of liquid that is determined by the length of the stroke of the piston 14. The cylinder 12 rests upon a mounting plate 24. A base plate 26 comprises the bottom of the cylinder and suitable seal means is provided. At its upper extremity, the cylinder 12 is received by a housing 28 which is connected to the mounting plate 24 by pin-type fasteners 29.

The piston 14 reciprocally moves within the cylinder 12 to draw liquid into the cylinder on its upstroke and force the liquid out of the cylinder into a container on its downstroke. A piston rod 30 extends upwardly from the piston 14 and passes through the upper wall of the cylinder which carries packing 34. The space above the piston is vented to atmosphere through openings 33. A gasket 32 carried by the piston prevents leakage therepast.

The liquid is drawn through the inlet 16 by a partial vacuum created upon retraction of the piston 14 within the cylinder 12. The inlet 16 includes an opening through the base plate 26 into the cylinder 12 and connects to a source of the liquid (not shown). Within the inlet 16, there is positioned a check valve (not shown) which permits flow in only one direction, i.e., upward into the cylinder 12. Normally, the check valve is closed. However, when the piston 14 is moving upward within the cylinder 12, the valve element of the check valve is drawn upward to provide free communication from the inlet 16 into the cylinder 12.

In the outlet 18 of the metering pump through which the liquid is dispensed, a check valve element 56 is positioned between an outlet opening 57 in the base plate 26 and an outlet'pipe 58, which leads to the nozzle 20. The outlet valve illustrated in FIG. 1 and the inlet check valve (not shown) are of substantially the same construction although other suitable valves can also be used. Plural passageways 59 about the periphery of the valve element allow liquid forced from the cylinder 12 by the advancing piston 14 to pass into the outlet pipe 58. A globe 60 at the upper end of the valve element 56 engages a tapered seat 62 formed in the base plate 26 to normally close the outlet opening 57'except when the piston 14 is moving downward. To maintain the valve element 56 in this closed position, a spring 64 is disposed below the valve element which urges it upwardly into engagement with the seat 62. When the piston 14 is driven downward within the cylinder, the liquid pressure overcomes the urging of the spring 64 to unseatthe valve element. When the valve has been forced to its lowermost position by the liquid pressure, the liquid flows through the passageways 59. l

The outlet pipe 58 has a collar 74 which is connected to the body of the check valve by a quick-release clamp (not shown) so that the outlet pipe can be readily removed from the outlet 18 for cleaning. The outlet pipe 58 projects first downwardly from the outlet valve element 56 and then bends at a 90 angle to extend substantially horizontally. correspondingly, the nozzle includes a branch pipe .80 which projects horizontally therefrom and which is located intermediate the ends thereof. This pipe 80 is joined to the end of the outlet pipe 58 by a connector 81 so that the liquid flowing out of the main cylinder is directed into the nozzle 20.

The nozzle 20 dispenses the liquid forced from the cylinder 12 downward into a container, such as a partially formed, open-top carton w-en the liquid is milk. The nozzle 20 is laterally offset from the axis of movement of the outlet valve element 56 to a location where it will overlie a conveyor or the like. Accordingly, the nozzle 20 can be disposed at any convenient distance from the remainder of the metering pump 10 and need not be located directly beneath the cylinder 12.

The features of the nozzle 20 and the hollow discharge valve element 22 for controlling the flow of foamable liquid are illustrated in FIGS. 2, 3 and 4. The outer casing 82 of the nozzle is generally cylindrical in shape but diverges outwardly near its lower end to provide a bell-shaped portion 83 having a progressively increasing internal crosssectional area. The movable shaft 91 and rests just above the top surface of the cas- 4 ing. A pair of openings 109 are provided in the sidewall of the hollow shaft 91 near its upper end, and a twopiece spring-loaded cap 84 is detachably secured to the upper end of the hollow shaft 91 to hold it in operative position. A spring 94 surrounds the upper end of the shaft and is seated at its lower end upon the upper surface of the collar 92. The upper end of the spring 94 fits into the underside of a lower section 85 of the cap, and when the lower section is depressed, a cooperating upper section 86 can be slidinto engagement with the upper end of the shaft 91 above the openings '109. When the lower section 85 is released,- the spring 94 locks the two sections 85, 86 in engagement. Thus, the I spring 94 normally biases the cap 84 and the movable discharge valve element 22 upward to close the nozzle. The spring 94 is selected so its force is overcome and the nozzle opens when the liquid pressure in the pipe reaches about 3 psi. The bottom rim of the lower cap section engages the upper surface of the collar 92 to prevent further downward movement of the valve element within the nozzle, thus defining the extent to which the nozzle 20 opens.

The nozzle opens quickly when the piston 14 begins to descend within the cylinder 12. The movable valve element-22 generally conforms tothe internal shape of the casing. The lowermost portion .has the general shape of a bell andhas a peripherallip 106 at the bottom thereof to deflect the liquid outward generally against the innersidewalls of the carton to be filled. The valve element 22 is made proportionately smaller than the interior dimensions of the casing to provide an annular passageway 95 of desired size between the casing 82 and the outer surface of the valve'element; through which the liquid passes to be dispensed. As;

lntermediate the ends of the discharge valve element 22, an annular surface extends about the periphery of the valve element slightly beneath the connection to the outlet pipe branch 80 and is normal to the axis of movement of the valve element. A flow diverter 101 having spaced openings 102 directs the liquid flowing from the branch 80 substantially completely about the annular surface 100. The flow diverter 101 is disposed about the shaft 91 of the valve element in a chamber in the upper part of the casing 82, and the annular surface 100 engages the underside of the flow diverter 101 to define the uppermost closed position of the valve element 22 within the nozzle casing 82. In FIG. 3, the flow diverter 101 is shown in its upper position where it provides a direct path for liquid to the annular surface 100,

and the downward pressure overcomes the spring 94 causing the valve element 22 to move downward within the nozzle casing to a position where the annular surface lies adjacent an annular recess 103 in the casing. The flow diverter 101 moves downward with the valve element 22 to block the direct passageway and cause the liquid to flow up over the surface of the diverter and then down in the region 105 between the outer surface of the shaft and the inner surface of the diverter. This arrangement assures good distribution of liquid throughout all 360. A path for the liquid is thus defined through the outlet pipe 58, the branch pipe 80, the flow diverter 101, the recess 103 and the annular passageway 95, the liquid exiting from the nozzle over the lip 106 and being directed against the sidewalls of the carton being filled.

Disposed upon and equiangularly spaced about the periphery of the discharge valve element 22 are three projections or guides 104, as shown in FIGS. 3 and 4. The guides 104 bear against the interior surface of the casing 82 of the nozzle 20 between the recess 103 in the casing and the diverging portion 83 thereof to guide the sliding movement of the lower portion of the discharge valve element 22 within the casing.

The lip 106 at the lowermost extremity of the discharge valve element 22 conforms to the shape of the interior bottom of the casing. To prevent foaming, the lip slopes downward and outward to direct the liquid outward against the sidewalls of the container to be filled so that the liquid impinges in a sheet against the walls at a location above the liquid level to minimize entrapping foam-causing air. The lip is held adjacent the lower end of the correspondingly flared diverging portion 83 of the casing 82 and closes the outlet at the end of the filling stroke. The lip 106 need not tightly seal the outlet but can be slightly smaller in diameter than the internal diameter of the casing 82, so that manufacturing tolerance can be easily met. So long as the gap does not exceed about 0.015 in., the surface tension of the liquid will maintain the liquid trapped within the outlet when the valve is closed.

It is a particular feature of the illustrated embodiment that the discharge valve element 22 is hollow. The air displaced from the container upon the charging of the liquid therein accordingly passes through the interior of the hollow valve element 22 and is vented to the atmosphere through apertures 109 near the upper end of the shaft 91 and then under the cap through scalloped openings 110. Discharge of the air displaced from the container through the hollow valve element 22 allows 360 liquid dispensing and separate unobstructed removal of the air, which contributes to retarding foaming of the liquid.

Located between the shaft 91 of the valve element 22 and the casing 82 of the nozzle 20 is a seal 110 of the O-ring type. This O-ring 110 prevents leakage between the shaft 91 and the upper end of the casing wherein the shaft reciprocates. The O-ring 110 seals the upper end of the movable valve element during the dispensing portion of the cycle when the liquid pressure in the easing is at its highest level. The design of the O-ring arrangement afi'ords long and maintenance-free service. The O-ring 110 is under maximum compression only during the short periods when the discharge valve is open and is substantially relieved when the discharge valve is open and is substantially relieved when the discharge valve is closedthus adding greatly to its life span. Furthermore, the O-ring 110 is under its greatest compression during the filling cycle when it is functioning to maintain the liquid under pressure within the easing. The O-ring 110 is positioned upon a tapered seat 1 12 formed by a countersink in the upper surface of the casing 82. The O-ring is slightly larger than the countersunk region so that the collar 92 which rests upon the O-ring is spaced slightly above the casing 82. When the valve element 22 is in its closed position, the only pressure on the O-ring is that of the compression spring 94- which is in its most extended position, thus reducing wear on the O ring 110, when the shaft 91 slides therethrough.

Referring now to FIG. 1 of the drawing, there is illustrated a drive system 118 for moving the piston 14 either up or down within the cylinder 12. The drive system 118 preferably comprises a double-acting hydraulic cylinder 120, although it should be appreciated that another suitable drive system for reciprocating the piston 14 within the cylinder 12 could be employed. The illustrated hydraulic cylinder 120 has a bore of about 1 it inches and includes a pair of ports 122 and 124 adjacent opposite ends to permit the entry and exit of noncompressible hydraulic fluid. The drive cylinder 120 is suitably mounted by a coupling 125 which connects its lower end to the housing 28 and at its upper end carries an adjusting unit 130. The coupling 125 screws onto the lower end of the cylinder and is mated to the top of the housing 28 by a quickdisconnect connector. A double-acting piston moves within the cylinder 120 in response to the entrance of fluid into either port 122 or 124. The illustrated piston has a maximum stroke of about 3 inches and is mounted in a manner to nominally produce a stroke of slightly less than 2 k inches. The piston has a lower threaded rod extension 127 which is suitably linked to the piston rod 30 and an upper unthreaded extension 128 (FIG. 5 which slides within the adjusting unit 130.

The adjusting unit 130 can best be seen in FIG. 5 of the drawing and functions to counteract play caused by construction tolerances and to accommodate variations in the specific gravity of the product being dispensed. An outer housing 131 of the adjusting unit 130 is mounted by screwing it onto the externally threaded upper end of the cylinder 120. The piston rod extension 128 slides within the bore 133 of an externally threaded sleeve 132 which in turn is mounted within an internally threaded mandrel 134. The mandrel 134 is rotatably mounted within the housing 131. The lower end of the sleeve 132 is slotted, and a pair of roll pins 135 extend into the slots 136 in the sleeve 132 to prevent the sleeve from rotating relative to the housing 131. A retaining ring 137 limits the distance the sleeve 132 can be moved upward in the mandrel 134 and prevents inadvertent disengagement of the pins 135 from the slots 136. The pins 135 are mounted in a lower insert section 138 of the housing 131 which is suitably secured in place in the lower end of the housing after the retaining ring 137 is installed. A knurled knob 139 is connected to the mandrel 134 by a set screw 140 and entraps the mandrel in the housing 131. Thus, manual rotation of the knob 139 and the interconnected mandrel 134 repositions the sleeve longitudinally with respect to the housing 131 and the drive cylinder 120.

The adjusting mechanism 130 functions by physically limiting the distance which the piston rod extension 128 can move upward, and thus it controls the length of the stroke of the double-acting piston in the cylinder 120. The arrangement employed in the illustrated embodiment is such that the downstroke of the cylinder 120 is controlled by the internal characteristics of the cylinder itself. The normal mounting and means 130.

connection to the lower piston rod 127 is such that the main piston 14 stops about one-quarter inch from the lower end of the main cylinder 12. Accordingly, the

volume of fill is controlled by the precise adjustment in the termination of the upstroke;

As previously indicated,.the upper rod extension 128 travels in the main bore 133 within the externally threaded sleeve 132. At a predetermined distance intermediate the ends of the sleeve 132, the diameter of the bore 133 is reduced to create an upper section 133a change in the longitudinal location of the sleeve 132 relative to the housing 131 and the drive cylinder 120 will effect a corresponding change in length of the stroke. This change in stroke length is effected by the rotation of the knurled knob 139, which may be provided with a suitable detent 142 for engagement with the exterior surface of the housing 131 which in turn may be marked withvsuitable indicators to denote the relative position of the sleeve 132 within the adjusting Repositioning of the sleeve 132 also results in repositioning a damping unit 144 mounted thereabove. The damping unit 144, (FIG; which is mounted above the adjusting unit 130, is adapted to progressively brake the movement of the piston rod 30 as the piston 14 nears the upward end of the refilling stroke of the cylinder 12. Because of. the timing of the overall machine of which the pump is a part, it is desirable that the upstroke be accomplished in about one-half the time of the downstroke. Thus fluid is supplied to the drive cylinder 120 on the upstroke at a rate twice that on the downstroke. Damping the final upward move ment prevents rebounding at the end of the stroke, which could create a momentary pressure surge in the outlet line-58 which would cause the discharge valve element 22 to pop open, thereby resulting in liquid spitting from the lip 106 of the nozzle. The damping unit 144 is connected to the adjusting unit 130 by an internally threaded adapter 146 which is screwed to the end of the threaded sleeve 132. The adapter 146 is joined at its upper end by a quick release clamp 147 which joins it to the lower end of the damping unit 144. A nut 148 locks the adapter 146 in place on the end of the sleeve 132. The rod actuator 143 extends internally of the sleeve 132 in the bore 133a. A button 149 of larger diameter than the bore 133a rests atop the end of the sleeve 132 and holds the actuator 143 in the position illustrated in FIG. 5. The lower end of the actuator extends below the shoulder 141 where it is in position to be engaged by the upper end of the piston rod extension 128 at the end of the upstroke.

The damping unit 144 operates by regulating the exit flow of hydraulic fluid from the double-acting cylinder on its upstroke. The damping unit 144 generally comprises a plunger 152 reciprocally movable in a passageway 153 in a plunger housing 154, which plunger is operated when contacted by the rodactuator 143. As illustrated in FIG. 6, the plunger 152 includes a right circular cylinder having a V-shaped notch 156 at the upper edge thereof. The notch 156- extends downward on the peripheral cylindrical surface 156 of the plunger and radially into the upper surface 158 I thereof. The notch 156 has its greatest width at the upper edge of the plunger. Thus, the notch 156 progressively increases in cross-sectional area in' the direction toward the upper surface 158 of the plunger. An annular groove 160 formed near the bottom of the plunger carries a suitable O-ring which prevents fluid leakage out the bottom of the plunger housing 154.

A first lower port 163 extends into the plunger housing 154 at a location generally near the lower end of the passageway 153 in which the plunger 152 reciprocates, as shown in FIG. 5. An annular recess 164 is provided in the housing 154 about the passageway 153 at the location of its junction with the port 163.'A second upper port 165 enters the housing and connects ,to the passageway 153 at a location intermediate the ends of the passageway. As shown in FIG; 1, a line 164 connects the upper port 122 of the double-acting cylinder 120 with the upper port 165 so that hydraulic fluid passing to or from the upper end of the double-acting hydraulic cylinder 120 must pass through the damping unit 144. In operation, whenever the piston 14 is being driven upward on its refilling stroke, the fluid being forced from the port 122 at the upper end of the double-acting cylinder 120 and is carried by the line 164 into the upper port 165 of the damping unit 144.

When the piston 14 is in its lowermost position within the cylinder 12 after having dispensed the liquid, the rod actuator 142 is in its lowermost position,as illustrated in FlG.5. In this position, the plunger 152 rests upon a retainer 166 that is inserted within the lower end of the plunger housing 154, which retainer has a central hole large enough to permit the button 149 of the actuator to pass upward therethrough. in this position, the upper surface 158 of the plunger 153' is generally aligned with the lower port 163 so there is free communication of fluid between the ports 163 and 165 of the damping unitthrough the passageway 153. There is also communication between the ports 163 and 165 through a by-pass 168 so that the hydraulic fluid readily flows between the ports during the initial part of the upstroke of the main piston 14.

Disposed about a guide 172 projecting upwardly from the upper surface 158 of the plunger, there is located a coil spring 170. When the plunger 152 is in its lowermost position, the spring is uncompressed. As

the piston 14 nears the end of its upward stroke within the main cylinder, the upper end of the drive rod extension 128 engages the bottom of the actuator 143 forcing it upward. The button 149 at the top of the actuator 143 engages the undersurface of the plunger 152 moving it upward. Upward movement at the plunger 152 in the passageway 153 quickly causes the spring 170 to engage the ,underside of a circurnscribing holder 174. The spring holder 174 has a central orifice 175 which terminates at its upper end in a tapered seat 176. The seat 176 is proportioned to mate with the lower end of a plug 178 which depends from a cap 180 that has exthrough the by-pass 168 is eliminated. The location of the holder 174 determines whether there will be flow through the by-pass 168, and the construction of the holder 174 is designed to facilitate flow through the bypass 168 during the major portion of the upstroke where the hydraulic fluid is pumped at a rate twice as fast as it is during the downstroke of the piston 14.

At the same time as fluid flow through the by-pass 168 is being eliminated by the seating of the plug 178, the fluid flow from the upper port 165 into the lower port 163 through the central passageway 153 is being restricted by the upward movement of the main body of the plunger 157 which has risen to a position where the upper surface 158 of the plunger is above the top of the annular recess 164 so all of the fluid flow must now pass through the peripheral notch 156. As can be seen in FIG. 6, the cross sectional area of the notch 156 decreases progressively downward. Accordingly, rate of flow of fluid gradually decreases, thus effecting a corresponding smooth slowing of the movement of the drive piston in the brief time interval just prior to contact of the upper extension 128 with the shoulder 141 that terminates the more rapid upstroke. By progressively restricting hydraulic fluid flow through the notch 156, this damping unit 144 eases the end of the upward stroke, preventing any abrupt stop in the refilling of the main cylinder with a product, such as milk, that could otherwise result in spitting at the nozzle.

In operation of the metering pump 10, the foamable liquid, such as milk, to be dispensed is drawn into the cylinder through the inlet 16 upon the upstroke of the piston 14 which creates a partial vacuum within the cylinder. As the piston 14 is forced downwardly within the cylinder by the hydraulic drive system 118, the liquid is forced under pressure through the outlet 18 past the outlet valve element 56. The liquid entering the nozzle casing 89 applies sufficient force to the upper surface 100 of the hollow discharge valve element to overcome the force of the spring 94 and open the nozzle. Liquid is dispensed in a 360 continuous ring through the annular passageway 95 and impinges upon the container sidewalls at a level above that of the liquid level in the containers being filled. The air displaced from the container exits smoothly upward through the center of the hollow discharge valve element 22 and is vented to the atmosphere through the apertures 109 at the upper end of the valve element and the openings 110 in the bottom rim of the cap lower portion 85. The O-ring 110 excellently seals the upper end of the valve element because it is under its greatest loading when the nozzle is open and the liquid pressure is at its maximum.

On the pumping stroke of the piston 14, the by-pass 168 and the passageway 53 through the damping unit 144 quickly open, and the unit does not interfere with fluid flow. As the piston 14 retracts within the cylinder 12, the damping unit 144 smoothly decelerates the piston to prevent fluid rebound that could result in the hollow valve element 22 popping open and consequent foaming and spitting at the nozzle 20.

While one form of the invention has been shown and described, it should be apparent that various modifications could be made therein without departing from the spirit and scope of the invention.

Various of the features of the invention are set forth in the following claims.

What is claimed is:

1. A metering pump comprising a pumping cylinder having an inlet and an outlet, valve means in said inlet and in said outlet, a piston mounted for reciprocating movement in said inlet and in said outlet, a piston mounted for reciprocating movement in said cylinder for drawing liquid thereinto through said inlet and for forcing the liquid therefrom under pressure through said outlet, means for reciprocating said piston, nozzle means for directing the liquid into a container, means connecting said nozzle means to said outlet, said nozzle means including a housing and a hollow discharge valve element proportioned to fit within a first opening in said housing and thereby defining first passageway means between the interior surface of said housing and the exterior surface of said discharge valve element through which the liquid passes on way to the container, biasing means for urging said discharge valve element into position adjacent said housing to close said first passageway, and vent passageway means extending through said hollow valve element and exterior of said housing whereby air being displaced from the container into which the liquid is directed is vented through the interior of said hollow discharge valve element.

2. A metering pump in accordance with claim 1 wherein said discharge valve element terminates in a circular rim and said first passageway is generally annular whereby liquid is dispensed about all 360 of said rim.

3. A metering pump in accordance with claim 1 wherein said discharge valve element is slideably mounted within said housing and wherein said biasing means is overcome solely by the pressure of liquid being delivered by said pumping cylinder bearing against said discharge valve element.

4. A metering pump in accordance with claim 3 wherein said discharge valve element has a hollow shaft portion, wherein said housing has a second opening coaxial with said first opening in an opposite surface therefrom through which said hollow shaft portion extends and wherein said biasing means is connected to said hollow shaft portion at a location exterior of said housing.

5. A metering pump in accordance with claim 4 wherein said housing includes inlet means connected to said cylinder outlet, which inlet means is located intermediate said first and second openings and wherein said housing contains second passageway means leading from said inlet means to an exterior surface of said valve element whereby liquid being pumped through said inlet means applies sufficient force to said exterior surface to cause said discharge valve element to overcome the force of said biasing means and slide within said housing to open said first passageway means and allow liquid discharge.

6. A metering pump in accordance with claim 4 wherein an O-ring surrounds said hollow shaft portion to provide a seal between said shaft and said second opening through said housing, wherein collar means is disposed about said shaft portion having one surface in contact with said O-ring and wherein said biasing means engages the opposite surface of said collar means thus loading said O-ring.

7. A metering pump in accordance with claim 6 wherein said biasing means is a compression spring disposed about said hollow shaft portion, wherein cap position.

mounted above said drive cylinder andwherein means for damping the final portion of the refill stroke of said piston is mounted above said adjusting means and hydraulically connected to an upper hydraulic port of said double-acting cylinder.

9. A metering pump in accordance with claim 8 V wherein said damping means comprises a plunger located for mechanical engagement by a piston rod extension of said double-acting drive cylinder and adapted for sliding movement in a bore in a plunger housing, said plunger having a V-shaped notch formed therein which diverges inra direction away from said piston rod extension, a pair of ports communicating with said bore in said plunger housing and one of said ports being in hydraulic connection with said upper port of said double-acting cylinder sothat movement of said plunger upon engagement by said piston rod extension near the end of the refill stroke progressively restricts the flow of said fluid between said ports to passage through said notch which thus damps the final movement of said piston on the refill stroke.

10. A dispenser for filling a container with liquid comprising a housing having a nozzle opening, inlet means for connection to means for supplying liquid under pressure, a valve element disposed in said housing and proportioned to close said nozzle opening,

means mounting said valve element in said housing for movement between a closed position and an open position where a generally annular passageway isprovided for liquid to flow outward between the interior surface of said nozzle opening and the exterior of said valve element, said valve element having an internal vent passageway. so that air displaced from the container by liquid flowing thereinto is vented therethrough, and means biasing said valve element 1 l. A metering pump comprising a pumping cylinder having a reciprocating piston disposed therein, inlet "and outletvalves associated with said cylinder for controlling liquid flow thereto and therefrom, normallyclosed nozzle means in fluid communication with said outlet valve, said nozzle means opening automatically in response to liquid pressure from said pumping cylinder to discharge liquid therethrough and into a container to be filled, a double-acting hydraulic drive cylinder connected to said-pumping cylinder, said piston being connected to a piston rod at one end of said drive cylinder, means for mechanically altering the stroke of said drive cylinder attached to the opposite. end of said drive cylinder, hydraulic damping means mechanically mounted at the end of said adjusting means opposite from that attached to said drive c linder, rgea ish cans in U1 co adjacent said opposite end of said drive cylinder so that hydraulic fluid entering or leaving said opposite end port of said drive cylinder passes through said damping means, and mechanical actuating means disposed interior of said adjustingmeans for linkingsaid damping means to the end of the piston rod extending from said opposite endof said drive cylinder.

to a normally closed Patent No 3 I 6 Inventor(s) Column 2,

Column 2 Column 3,

I Column 5,

Column Column 8,

Column 8,

Column 9,

Column 9,

(SEAL) mints STATES PATENT" @FFTLCE Robert B. Encke line 36, change line 39 change line 44, change delete line 58,

line 59, delete line 26, delete line 3 0, change line 38, change line 55, change QERTEFECATE GEE CQREREQTEQN Dated Aug, 22, 1972 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, delete lines 55, 56 and 57.

"elements" to --element-.

"w-en" to -'when-.

"discharge".

II I

"53" to --l53.

Column-l0, lines 5-6, Claim 1: "delete "in'said inlet and in said outlet, a piston mounted for. reciprocating movement" Signed and sealed this 29th day of May 1973.

Attest:

EDWARD M .FLETCHER,JR.

Attesting Officer F ORM PO-1OSD (10-69) ROBERT GOTTSCHALK Commissioner of Patents USCOMM'DC 50376-1 69 U.S. GOVERNMENT PRINTING OFFICE: 1969 O366-33A. 

1. A metering pump compRising a pumping cylinder having an inlet and an outlet, valve means in said inlet and in said outlet, a piston mounted for reciprocating movement in said inlet and in said outlet, a piston mounted for reciprocating movement in said cylinder for drawing liquid thereinto through said inlet and for forcing the liquid therefrom under pressure through said outlet, means for reciprocating said piston, nozzle means for directing the liquid into a container, means connecting said nozzle means to said outlet, said nozzle means including a housing and a hollow discharge valve element proportioned to fit within a first opening in said housing and thereby defining first passageway means between the interior surface of said housing and the exterior surface of said discharge valve element through which the liquid passes on way to the container, biasing means for urging said discharge valve element into position adjacent said housing to close said first passageway, and vent passageway means extending through said hollow valve element and exterior of said housing whereby air being displaced from the container into which the liquid is directed is vented through the interior of said hollow discharge valve element.
 2. A metering pump in accordance with claim 1 wherein said discharge valve element terminates in a circular rim and said first passageway is generally annular whereby liquid is dispensed about all 360* of said rim.
 3. A metering pump in accordance with claim 1 wherein said discharge valve element is slideably mounted within said housing and wherein said biasing means is overcome solely by the pressure of liquid being delivered by said pumping cylinder bearing against said discharge valve element.
 4. A metering pump in accordance with claim 3 wherein said discharge valve element has a hollow shaft portion, wherein said housing has a second opening coaxial with said first opening in an opposite surface therefrom through which said hollow shaft portion extends and wherein said biasing means is connected to said hollow shaft portion at a location exterior of said housing.
 5. A metering pump in accordance with claim 4 wherein said housing includes inlet means connected to said cylinder outlet, which inlet means is located intermediate said first and second openings and wherein said housing contains second passageway means leading from said inlet means to an exterior surface of said valve element whereby liquid being pumped through said inlet means applies sufficient force to said exterior surface to cause said discharge valve element to overcome the force of said biasing means and slide within said housing to open said first passageway means and allow liquid discharge.
 6. A metering pump in accordance with claim 4 wherein an O-ring surrounds said hollow shaft portion to provide a seal between said shaft and said second opening through said housing, wherein collar means is disposed about said shaft portion having one surface in contact with said O-ring and wherein said biasing means engages the opposite surface of said collar means thus loading said O-ring.
 7. A metering pump in accordance with claim 6 wherein said biasing means is a compression spring disposed about said hollow shaft portion, wherein cap means attached to the end of said hollow shaft compresses said spring between it and said collar means, and wherein a depending rim portion of said cap means engages said collar means in the fully open position to load said O-ring directly when said discharge valve element is open and the liquid pressure is at its greatest value.
 8. A metering pump in accordance with claim 1 wherein said means for reciprocating said piston includes a double-acting hydraulic drive cylinder, wherein means for altering the stroke thereof is mounted above said drive cylinder and wherein means for damping the final portion of the refill stroke of said piston is mounted above said adjusting means and hydraulically connected to an upper hydraulic port of said double-acting cyliNder.
 9. A metering pump in accordance with claim 8 wherein said damping means comprises a plunger located for mechanical engagement by a piston rod extension of said double-acting drive cylinder and adapted for sliding movement in a bore in a plunger housing, said plunger having a V-shaped notch formed therein which diverges in a direction away from said piston rod extension, a pair of ports communicating with said bore in said plunger housing and one of said ports being in hydraulic connection with said upper port of said double-acting cylinder so that movement of said plunger upon engagement by said piston rod extension near the end of the refill stroke progressively restricts the flow of said fluid between said ports to passage through said notch which thus damps the final movement of said piston on the refill stroke.
 10. A dispenser for filling a container with liquid comprising a housing having a nozzle opening, inlet means for connection to means for supplying liquid under pressure, a valve element disposed in said housing and proportioned to close said nozzle opening, means mounting said valve element in said housing for movement between a closed position and an open position where a generally annular passageway is provided for liquid to flow outward between the interior surface of said nozzle opening and the exterior of said valve element, said valve element having an internal vent passageway so that air displaced from the container by liquid flowing thereinto is vented therethrough, and means biasing said valve element to a normally closed position.
 11. A metering pump comprising a pumping cylinder having a reciprocating piston disposed therein, inlet and outlet valves associated with said cylinder for controlling liquid flow thereto and therefrom, normally-closed nozzle means in fluid communication with said outlet valve, said nozzle means opening automatically in response to liquid pressure from said pumping cylinder to discharge liquid therethrough and into a container to be filled, a double-acting hydraulic drive cylinder connected to said pumping cylinder, said piston being connected to a piston rod at one end of said drive cylinder, means for mechanically altering the stroke of said drive cylinder attached to the opposite end of said drive cylinder, hydraulic damping means mechanically mounted at the end of said adjusting means opposite from that attached to said drive cylinder, means hydraulically connecting said damping means in fluid communication with the hydraulic port adjacent said opposite end of said drive cylinder so that hydraulic fluid entering or leaving said opposite end port of said drive cylinder passes through said damping means, and mechanical actuating means disposed interior of said adjusting means for linking said damping means to the end of the piston rod extending from said opposite end of said drive cylinder. 